Shaving the beard during Ramadan does not break the fast, but it does detract from the reward of the fasting person.

Acid reflux is something that happens involuntarily. A person may feel some acidity or bitter taste in his esophagus but it does not reach the mouth. In this case, it does not break your fast because it does not come out to the mouth.

Chewing gum which contains sugar and artificial flavorings breaks your fast. But if the gum does not contain any substance that will dissolve and enter the stomach, then it does not break the fast.